Tele Vue Plössl 20mm — image 1
Tele Vue

Tele Vue Plössl 20mm

A 20mm Tele Vue Plössl: a low-power eyepiece for framing large nebulae, galaxies and open clusters, from the reference Plössl, the four-element design executed to the standard every other Plössl is judged against.

76/ 100
Polaris Score
Optical quality · Immersion · Comfort · Value
See the breakdown ↓
What it's for
Low power · wide fieldHigh power · narrow field

Low power. At 20mm this is a low-power eyepiece for framing large nebulae, galaxies and open clusters; it is not the eyepiece for high-power planetary detail.

Apparent Field
50°
Barrel Size
1.25"
Eye Relief
14mm
Focal Length
20mm
From$138

Lowest in 90 daysLowest ever tracked

Price tracked by PolarisObserved 101 timesTracking since Jul 2026

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The spacewalk

You don’t look at a field.
You look into the sky.

Every number on the spec sheet matters less than one feeling: how much sky wraps around your eye. Widen the apparent field and watch the black edge of the eyepiece slip away.

50° apparent field

At 50°, you are aware of the field edge, like looking down a short, comfortable tube.
Try this eyepiece on your own scope in the Simulator →
01What it's good at

What it's best at — and the trade-offs.

Immaculate build, coatings and QC that hold their value for decades.
Best at
✓Immaculate build, coatings and QC that hold their value for decades.
✓A neutral, honest 50-degree view with no fuss, the eyepiece to trust a planet to.
✓At 20mm it lands squarely in low power territory, exactly where wide star fields and large objects belong.
Trade-offs
!Short eye relief below about 12mm, the unavoidable Plössl compromise.
!A 50-degree field is narrow next to modern wide-fields.
!You pay a real premium over a budget Plössl for build and coatings, not extra field.
02In your telescope

One eyepiece. A different job in every scope.

24× in a small refractor, 102× in a long SCT

An eyepiece has no magnification of its own — the telescope decides. The same eyepiece becomes 24× and 2.1° of sky in a little refractor, or 102× and a tight frame in a long SCT. Here’s what it does across common scopes.

Small apo refractor
480 mm · f/5.5
Magnification
24×
True field
2.1°
Exit pupil
3.6 mm
24× across a 2.1° field at a 3.6mm exit pupil, right in the deep-sky sweet spot, bright and easy on the eye.
8-inch Dobsonian
1200 mm · f/6
Magnification
60×
True field
50′
Exit pupil
3.3 mm
60× across a 50′ field at a 3.3mm exit pupil, right in the deep-sky sweet spot, bright and easy on the eye.
12-inch Dobsonian
1500 mm · f/5
Magnification
75×
True field
40′
Exit pupil
4.0 mm
75× across a 40′ field at a 4mm exit pupil, right in the deep-sky sweet spot, bright and easy on the eye.
8-inch SCT
2032 mm · f/10
Magnification
102×
True field
29′
Exit pupil
2.0 mm
102× across a 29′ field at a 2mm exit pupil, crisp medium power for galaxies, clusters and planetary nebulae.
Exit pupil is how wide the beam of light leaving the eyepiece is. Around 5–6 mm is bright and immersive under dark skies; push much past 6 mm and you waste light, and under light pollution a smaller exit pupil shows more contrast.
03In plain English

The numbers, in plain English.

20mm FL · 50° AFOV · 1.25"
Focal lengthLow to mid power
20mm
About 60x in an 8 inch f/5.9 Dobsonian and 102x in an 8 inch SCT. Comfortable for finding objects and high enough to keep the sky background dark behind them.
Apparent fieldClassic
50°
The traditional field width. At this focal length the true field is usable for locating targets, though a 68 degree eyepiece of the same power would show noticeably more sky at once.
Eye reliefComfortable
14mm
Fourteen millimetres is relaxed viewing without glasses and marginal with them. From here upward, the Plössl design stops asking anything uncomfortable of your eye position.
BarrelStandard
1.25"
Fits any telescope, with no adapters and no weight concerns even on a lightweight focuser.
OpticsReference simple design
Fully multi-coated
A simple, precisely made design whose small element count keeps scatter low and transmission high. It remains one of the most cost-effective ways to get a genuinely sharp view.
04What comes alive

The targets this eyepiece was born for.

The Orion Nebula (M42), The Andromeda Galaxy (M31), The Pleiades (M45), The Double Cluster…
The Orion Nebula (M42)Comes alive
The Orion Nebula (M42)
Wings of nebulosity fill the field with the Trapezium embedded.
The Andromeda Galaxy (M31)Excellent
The Andromeda Galaxy (M31)
The bright core with its two companion galaxies framed.
The Pleiades (M45)Excellent
The Pleiades (M45)
The whole cluster with dark sky to spare around it.
The Double ClusterComes alive
The Double Cluster
Two open clusters glittering side by side in one view.
The Beehive (M44)Excellent
The Beehive (M44)
A loose scatter of bright stars, best at low power.
Large open clustersExcellent
Large open clusters
Bright, wide targets that want field, not magnification.
05Role in a collection

Where it sits in your eyepiece case.

Where it sits across 3 focal lengths

A good eyepiece collection isn’t a pile of glass — it’s two or three focal lengths that hand off from wide to tight. This is the anchor at the bottom of the ladder: the one you find and frame with. You buy it once, and it stays your low-power eyepiece for life.

20 mmThis one
Low power · wide field
Find, frame and sweep. Your widest true field and the lowest useful magnification, the eyepiece you reach for first.
Veil Nebula · Pleiades · Milky Way star clouds
13 mm
Medium power · the workhorse
Where most deep-sky objects look their best, galaxies, globulars and planetary nebulae at a comfortable scale.
M13 · Ring Nebula · most galaxies
7 mm
High power · detail
Planets, the Moon at the terminator, tight double stars and the smallest planetary nebulae. Steady-air nights only.
Jupiter · Saturn · lunar craters
06Build around it

What it pairs with.

The telescope · Pair it · Filter it
The telescope
What it goes into
Any 1.25-inch focuser
Fits essentially every telescope made.
Fast, short scopes love this field
A fast Newtonian or refractor turns this focal length into a rich, wide sweep.
Pair it
What extends its range
A high-power eyepiece (~12mm)
Locate and frame with this one, then swap to high power for planets and small objects.
Filter it
What transforms the view
A UHC or OIII nebula filter
At low power this eyepiece frames big emission nebulae; a narrowband filter makes the Veil and North America jump out.
07The Polaris Score

How it scores, and why.

76/100
76/ 100
Tele Vue Plössl 20mm

Judged as a low-power eyepiece for framing large nebulae, galaxies and open clusters, it earns its score on reference-grade on-axis sharpness and contrast: the plössl done exactly right. Tighter eye relief at this focal length is the main thing holding it back. A wide field is what this focal length is for, and it delivers.

Optical quality
86
Immersion
56
Comfort
76
Value
74

Polaris weighs how well the eyepiece does the job it was designed for — optics, immersion, comfort and value — never list price or brand.

08Who it's for

An honest fit check.

Observers who want a low-power eyepiece for framing large nebulae, galaxies and open…
Buy it if you
✓Observers who want a low-power eyepiece for framing large nebulae, galaxies and open clusters.
✓Observers happy to take their glasses off at the eyepiece.
✓Observers who value on-axis contrast over a sprawling field.
Look elsewhere if you
!Anyone who has looked through a wide-field eyepiece and cannot go back to a 52-degree tunnel.
!Eyeglass wearers, who will not comfortably reach the full field at this focal length.
!Planetary specialists who want the last ounce of high-power contrast from an orthoscopic.
09The numbers

Full specifications.

4 measured and stated values
Optical
Focal Length20mm
Apparent Field50°
Comfort & handling
Eye Relief14mm
Fit & build
Barrel Size1.25"
Editor’s Take

Sweep it across a rich star field and the reason to own this focal length is obvious in a second. That is what the Plössl is for.

— The Skynocular verdict
10Alternatives

For a different goal, start here.

3 alternatives, each mapped to the goal it wins at
Wider, lower power

Tele Vue Plössl 32mm

The same optics with more true field, for framing larger objects and finding your way around.

→
More magnification

Tele Vue Plössl 11mm

The same line at higher power, for planets and the smallest deep-sky detail.

→
Cross-shop

Tele Vue Delos

A natural alternative at a similar price point, if you want to compare field and feel before committing.

→